The rib cage, along with the skull and the pelvis, is one of the important, fairly unchanging bony structures of the figure. If you can capture the spine and rib cage, and then hang the shoulder girdles (the scapulae in back and clavicles in front) off of it properly, you've gone a long way toward defining the form of the upper body. Here's my simplified conception of its form.
The form is a lot like an egg with the top and bottom cut off.
The bones "sag" off of the spine so that the front every rib is lower than the back.
The first set of ribs is the same as the neck hole.
The spine seems fairly deep inside the rib cage because the ribs arch off the spine like valentine hearts, not simple hoops.
The ribcage is widest around the eighth ribs - not widest around the center (fifth) ribs, as it would be if it were a simple ellipsoid.
Here is a simplified approximation of the relationship between the spinal column and the rib cage as I understand it. It's not perfect, and the stripes are meant to convey surface information, not to be literal tracings of each bone. But I think it's a useful tool in grasping the rib cage.
Hi,
This post has ben really helpful, currenty im having real problems grasping the ribcage area. Ive currently moved on from just drawing from references and a now trying to see the figure as shapes ect. I was using Burne Hogarth book, using basic shapes, although is helped with other areas, i don't find it was that much with the rib cage, so am now going back to anatomy, hopefully i will finally get it!
BTW - your skull references have been hugely helpul as well.
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